Technical c10 Wheel Offset/Backspacing

So wondering what is a good wheel fitment for 1960 to 66 c10s.
I'm currently running aftermarket rims 15x7 with a 3.75 backspacing.
These wheels aren't what i'm liking so shopping for some other style. (steelie)
There are so many rim backspacing in the 15x6 to 8s .
I'm running 235 75s for tires.

 

Shouldn't be too hard to figure out. You know what you have. Measure the existing clearances inside and out. On the rear you should leave about 1" of clearance on either side. On the front steer the wheels lock to lock and observe/measure the clearances. With that information you should be able to establish the available range of change. Then you can find the wheels that satisfy your aesthetic.

 

For what its worth my 63 came from the PO with 15 x8 truck rallye steelies and I ran 235 70s. Im happy with the look so kept tne steelies. The only complaint is jow the fronts dont quite tuck under the fenders enough especially compared to the rear. I changed the fronts to 225 75, which helped a little but not enough.

Also when I did 2" drop spindles with front discs the end of the lower control arms where nicking the inboard wheel weights, which says I cant go more offset with 8"

 

The rears on my '65 were 8 wide and 3.375 (3 3/8) back space. 235-70R15

The fronts are stock 5 rims same back space with 205-70R15.

The early C-10s were all pretty close to the same.

Hope this helps a little bit.

 

Well hope the rims I ordered 15x7 with 4.125 backspaceing will be ok.
If not I'll have to swap to the 15x6 with 3.75 backspaceing.

 

If those are steel wheels they are probably 0 offset. If alloy, maybe .250"/6mm -offset.

The 4.125 backspace will have about .500"/12mm +offset. This will move the same size tires in toward the chassis center and less flush with the outer fender lip by the same approximate amount.

 

According To JEGS The Rims Are +3 offset with 4.125 backspacing heres the part number i ordered.
055-61B-57060 there Raceline 61B in 15x7s

 

On my 66 Suburban I took the "anything is possible approach" if you want it bad enough.
15"x12".

 

I am running 15x6 with 3.75” backspacing on my 66 with the same size tires and with stock rear axle and my tires rub on the inside of the wheel wells through turns. Not sure how low your pu is, but I wish mine were about 1/4” less backspacing. I just order the same basic wheels for my kids 63, but it is running a 72 rearend which is about 1/2” wider per side. I figure it should have plenty of clearance to the back with the same tires. I’m guessing you may have issue if your truck is lowered and your new wheels have more offset. If it’s stock height, or has a 5 lug rear axle, it is probably fine.

 

Well I had looked under as it currently sits an looks like there's room.
I'm gonna lower it eventually.
The wheels I ordered was only offered in 4.125 backspaceing in the 15x7.
Other options was the 15x6 with 3.75 .
However my wagon wheels are 15x7 but have the 3.75 backspaceing.
Guess I'll find out soon as I get them next day or so...

 

1/4" spacer? Maybe longer studs.

 

Yea, I actually pulled some 1/4” spacers off my kids pu so may try them to see if I clear better.

 

So I got the wheels today.
An they seem to fit ok.
Looks like everything will clear.
This offset/backspaceing actually moved the wheel inward 3/4" to